Organolithium compounds tert-butyllithium

Self-condensations are another set of important reactions of organolithium compounds. Tamao and Kawachi had reported that [(tert-butoxy diphenyl)silyl]lithium (20) exhibited ambiphUic character, and underwent a self-condensation reaction to give a [2- tert-butoxy)disilynyl]lithium derivative in THF as shown in Scheme 4, and also a nucleophilic substitution reaction with n-butyllithium . 

Treatment of 1,2,4-triazine 22 with organolithium compounds results in the formation of adducts 23 (yields 8-18%), whereas the reaction of 22 with tert- mX - or -butyllithium as C-nucleophiles affords the hexahydrotriazine 24 (Scheme 15) <2002J(P1)2549>. 

Note the use of the shorthand notation for n.-butyllithium (BuLi) and for butane (BuH). In some cases, a powerful organolithium base such as tert-butyllithium (36) can deprotonate a compound that is not normally considered to be an acid benzene, for example. er -Butyllithium reacts with benzene to give the conjugate base phenyllithium (39), along with 2-methyl propane (the conjugate acid). 

The data reported for a number of organolithium compounds in various states are given in Tables VI (13, 30, 32, 33, 34) and VII. The mass effect observed upon substitution of Li for Li is of particular interest, in that its magnitude is a rough measure of the extent to which lithium motion is involved in the normal mode. If only lithium motion were involved, the ratio of frequencies would be vu>lvu- = (7/6) , or 1.08. It is of interest that this ratio is observed for the aforementioned symmetric mode of the tert-butyllithium tetramer. This vibration can therefore be visualized as a symmetric motion of the lithium atoms along the local threefold axes of the tetramer. ... 

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